First Trimester of Pregnancy: 0-13 Weeks

Welcome to the first trimester of your pregnancy. We’ve compiled some handy information about how your little one is growing and what you, as a mom-to-be, can expect, plus some tips to keep in mind during this important period.

Your Baby’s Development in the First Trimester

During the first trimester of pregnancy, what starts as a tiny bundle of cells is quickly turning into a fetus that's about the size of a large plum. In these first trimester weeks, your little one’s heart, lungs, liver, spinal cord, head, and tiny limbs will form. Meanwhile, your uterus is fast becoming a comfortable home. By the end of the first trimester, the placenta and umbilical cord will also be in place.

Some exciting milestones in the first trimester include week 9, when your little one may start moving around (though you won't be able to feel these movements until the second trimester), and week 11, when your little one’s heart is beating loud enough to be heard at an ultrasound scan. By the end of month three, all essential organs and body parts will be in place — albeit in teeny-tiny size.

What You Can Expect in the First Trimester

Are you experiencing any of the typical first trimester pregnancy symptoms but still not sure if you're really pregnant? A home pregnancy test can confirm your hunch, and you can head to the doctor if you’re in any doubt. You’ll probably be curious about when your baby will arrive, so take a look at our handy due date calculator tool.

Some moms-to-be find the first pregnancy trimester quite challenging. You could be in for a ride on an emotional rollercoaster, as well as dealing with some annoying first trimester symptoms like tender breasts, constipation, cramps, and frequent urination.

If you experience nausea or “morning sickness” during the first trimester, you can think of this condition as a reassuring reminder that you are expecting a baby, while also trying to reduce the symptoms of morning sickness with some simple strategies. You might also notice some pregnancy cravings for unusual foods. Weird as they are, these are usually nothing to worry about.

Each week of the first trimester brings something interesting and new, so stay up-to-date with all these exciting changes using our pregnancy calendar. Before you know it, you’ll have made it to the second trimester.

What to Keep in Mind for the First Trimester

What you’re eating will naturally impact your growing little one, so it’s important to follow a healthy and nutritious pregnancy diet. Consult your healthcare provider about taking folic acid and prenatal vitamins. Learn about what is safe to eat and what isn’t — undercooked shellfish and unpasteurized cheeses should be avoided, for example. Alcohol, smoking, and drugs may be harmful, so it’s best to steer clear of these. As for those life-saving coffees (and chocolate bars), the recommendation is to limit your caffeine intake to 200 milligrams a day, the equivalent of a 12-ounce cup of joe.

The first trimester is also the time to find a good healthcare provider who can help you throughout your pregnancy and during childbirth.

Feeling exhausted? Try to relax and get plenty of rest in these early days. Building a new life takes a lot of energy. And, you've got two more trimesters to go before you'll meet your baby.